Collapsing Chambers

Collapsing chambers are rooms, caves, or other areas with a ceiling or floor that has partially fallen, entirely fallen, currently falling, or at risk of falling at any moment. They may lead to cave ins that crush the unwary or block passages. Often in narratives a collapsed chamber will mean that characters are trapped until they can find another way out.
If the collapse happened long ago, a skeleton may be stuck beneath the rubble.